How does one estimate what strength of Kevlar cord/tubular nylon/... to use in a rocket? A 1.5lb rocket flying on at most a G clearly needs less than a 5lb. rocket flying on H/Is, is there a way to estimate the potential load the system will experience? Empirical data gathering gets frustrating (ie:fly the rocket - if the cord breaks use a bigger one next time) while using the biggest cord one can buy gets heavy and expensive. Any ideas?